1. Technical Field
The present invention relates generally to a stereo image matching apparatus and method and, more particularly, to a stereo image matching apparatus and method, which generate an exact disparity map from stereo images using the maximum local support-area.
2. Description of the Related Art
The core purpose of stereo image matching technology is to obtain a disparity map for stereo images, and stereo images at that time are generally assumed to have undergone geometric camera calibration for two images. In this case, the range of search for disparities to find corresponding points is limited to one-dimensional (1D) horizontal Epipolar lines. However, typical matching between stereo images is problematic in that exact disparities cannot be calculated due to the difference in color and brightness between two images, the addition of noise, the occurrence of an overlap area, the existence of a repetitive pattern, the problem of boundary overreach on an object boundary, etc.
In particular, an adaptive window method that varies the size of a window or a multi-window method that utilizes windows having various sizes has been used to solve such object boundary overreach that occurs in the disparity map. However, it is very difficult to find an optimal window, and it is impossible to obtain the precise results only by matching object boundaries having random shapes using windows of a rectangular shape or another limited shape.
Meanwhile, a method of dividing images before matching the images has been proposed. However, it is very difficult to obtain precise division results for images having the complicated textures that frequently occur in ordinary images.
Therefore, an adaptive support-weight method in which weights proportional to distance to the color of the center of a window having a fixed size are assigned to the window, and a stereo matching method in which a geodesic support-weight method of adding connectivity from the center is applied to the adaptive support-weight method have been used. However, in an area having a fine repetitive pattern, a region having higher weights in the window is rapidly reduced, and thus a problem arises in that the matching discrimination ability decreases, and thus matching errors may increase.
Furthermore, an adaptive edge method that varies a window to be applied using edges has been attempted, but an additional task of extracting edges is required. In addition, when the size of a window is increased for the purpose of performing stable stereo matching against noise, the shape of edges becomes complicated. As a result, there is a disadvantage in that the number of windows that must be applied rapidly increases, thus causing the size of the windows to be limited.